Friedman DS40 just stopped working?!?

chrose1201

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HELP! My DS40 does not seem to want to play. First I should say it is at home and has not moved an inch. I played it yesterday all was fine. I keep the volume way down. The first thing I did was make sure the pedalboard was working. Then I checked the speaker connections. Then I isolated the cords and plugged them in direct. Then to be sure I took a known working cord and plugged it in. Nothing. The amp turns on, the volume is on but no sound comes out. Not even a hiss. Hopefully it's something simple. But I don't get it. NOTHING has changed since yesterday when it worked. Any thoughts?
 

chrose1201

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All tubes are glowing, fuse is intact. I tried turning all the knobs and oddly enough the only sound I got was when I turned the presence knob I got a scratching sound through the speaker.
 

ErictheRed

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There are two fuses, but anyway there's not a lot else that you can do on your own. FYI just because a tube is glowing doesn't mean that it's working.

The presence control adjusts the negative feedback out at the speaker side of things, so it makes sense that it's the only control causing any audible noise. Your signal is dead in the preamp or power section. Check both fuses and especially the rectifier tube.
 
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chrose1201

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Thanks. Both fuses are intact so if it's the rectifier tube it will have to be someone else fixing it. And after a year of owning it I finally have a gig coming up. I'd better be able to use it or I shall be an unhappy camper!
 

ARandall

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Rectifier and preamp tubes are plug n' play.
Power amp tubes usually require biasing so need a knowledgeable person with testing tools to adjust (exception is Cathode bias which are plug and play)
 

ErictheRed

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You can change all of the tubes yourself, no worries. If it ends up being a power tube causing the problem, you should probably have a tech bias it, however it won't hurt the amp to swap in some power tubes and fire it up to see if sound returns.
 

chrose1201

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You can change all of the tubes yourself, no worries. If it ends up being a power tube causing the problem, you should probably have a tech bias it, however it won't hurt the amp to swap in some power tubes and fire it up to see if sound returns.
Dave Friedman was good enough to write me back with his troubleshooting method. I will be dropping it off to the amp tech I use and let him mess with it so I don't F' it up :D
 

Hecubus

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I'm glad you found a solution that works for you. However, as others have said, this is totally something you can do yourself. My guy has a bench fee that keeps me from going to him with simple stuff.
 

chrose1201

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I'm glad you found a solution that works for you. However, as others have said, this is totally something you can do yourself. My guy has a bench fee that keeps me from going to him with simple stuff.
Understood. At the very least the way the guy is set up I can watch him do the troubleshooting and might well learn something so that I can do it in the future. I also have a friend that lives and breathes this stuff, but for a first time repair I'll take it to the approved tech first. Then later maybe to the other guy to mess around with the tubes.
 

chrose1201

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Thanks all, it was simple but a little detective work was done and in fact it was the pre-amp tube! Alls well that ends well!
 

DarrellV

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